Check your six
A term often used and popularized by the military to check at your 6 o'clock position. Which would be right behind you at any given point.
Sergeant: Private, check your six and tell me if you see any bogeys.
Private: Yes sir!
Private: Yes sir!
check your six
An expression used to inform someone that there's a target at their 6 o' clock position.
1: "Check your six."
2: "... Damn."
1: "Told ya."
2: "... Damn."
1: "Told ya."